It's not exactly been a secret that Apple sees iOS and OS X as points in a continuum, with increasingly similar user interfaces, standard applications, and pan-device services like iCloud, iMessage, iTunes, and Maps. But Apple left no doubt today with its announcements of OS X 10.10 Yosemite and iOS 8, to be released this fall at no charge, that its device future assumes you'll work on several devices as if they were multiple windows into the same computing space.

At first blush, the new OS X Yosemite looks like an iOS 7-skinned OS X, and in many ways it is. You get iO-like icons and transparency effects, as well as Siri-like search capabilities that straddle the Mac and the Web (which Google has been pioneering in Android).

But the real innovation is in what Apple calls Continuity, a set of services that have Macs, iPads, and iPhones interact automagically. For example, the devices keep tabs on what each is working on when in range, so you can hand off what you're working on from one device to another. You can start composing an email on an iPhone and pick up where you left off on the Mac.

Via iCloud Drive, Apple's iCloud sync-and-store service now finally lets you access documents in a Finder-like window, whether or not you have the same apps on all your devices. On iOS, you can use iCloud Drive to access third-party storage services like Dropbox and Box. iCloud Drive will also work on Windows PCs.

SMS text messages and phone calls on your iPhone are now accessible from your Mac, and you can place calls from your Mac via your iPhone. AirDrop -- Apple's peer-to-peer file sharing service among devices -- now works across iOS and OS X, and Macs can tell an iPhone via Wi-Fi to act as a hotspot without configuring the hotspot on the iPhone itself; you can essentially remotely initiate that hotspot session.

Safari for iPad also gains the live-tile tabbed view of OS X Yosemite and the Shared Links pane introduced in Safari 7, whch debuted in last year's OS X Mavericks.

On the iOS 8 front, beyond the Continuity capabilities common to OS X, Apple will add contextal predictive typing in all applications. In Mail, iOS 8 simplifies message flagging and deletion through more one-touch gestures. Messaging lets you add or remove individuals in group conversations and enable Do Not Disturb on a per-thread level, as well as more easily add photos and, for the first time, add audio attachments.

For developers, new app capabilities include the ability to extend their services to other apps, a major shift from the sandbox-based isolation in iOS that prevents malware attacks but limits interoperability. These extended services still run in the original app's sandbox, but use a Share sheets mechanism to become available to other apps. Also available in iOS 8 and OS X Yosemite is the ability to create widgets that can be added to the Notifications Center, and system-wide third-party virtual keyboards are also now supported.

Two sets of APIs -- HealthKit and HomeKit -- support health care devices and home automation devices. And the new CloudKit APIs provides developers a client-side programming model for iCloud authentication, storage, and other services.

iOS 8 also extends the TouchID fingerprint reader to third-party apps, so it can be used to unlock and confirm access on a per-app basis. The fingerprint information itself is kept local to the device and not shared with the apps that use it for verification. iOS 8 also enhances photo editing and adds the ability to search photos (and videos) both on your devices and in iCloud. All your photos are now available on all Apple devices, not just a subset as previously made available. A redesigned Photos app for OS X is due in early 2015.

What all this does is create a -- I hate to use this buzzword, but it applies here -- seamless experience across devices, turning computing more into what you do wherever you are with whatever you have. Both Google and Microsoft have similar notions in their platforms (Android and Chrome OS, and Windows and Windows Phone, respectively), but with nowhere near the same level of integration and commonality.

There are still those people who believe mobile is mobile and desktop is desktop and the two should only meet under chaperoned circumstances, but they're living in the past. Apple's OS X Yosemite and iOS 8 show the future.

InfoWorld executive editor Galen Gruman analyzes the latest issues in mobile technology and the consumerization of IT. He has also written or co-written more than 40 how-to books, on iOS, iPad, Windows 8, OS X, and desktop publishing.